47. Yup. I heard the sound of a four-engine piston-driven aircraft

last year. I ran out, and there was a B-17G flying less than 1000' above my house, headed on approach to the downtown St. Paul airport. WooHoo. It was on display there over a weekend. Sadly, that was the one that crashed less than two weeks later and was destroyed.

Since my father was a B-17 pilot, seeing one always gives me a thrill. Besides, it was really loud and the sound was unmistakable.